This invention relates to a semiconductor voltage regulator device for controlling an output voltage from an AC generator driven as by an internal combustion engine to a predetermined magnitude and more particularly to a construction of such a semiconductor voltage regulator device.
Semiconductor voltage regulator devices of the type referred to comprise the NPN type power transistor connected between ground and one end of a field winding disposed on an associated AC generator and excited with a full-wave rectified output voltage from the AC generator, and control circuit elements for controlling ON-OFF operation of the power transistor thereby to control the output voltage from the AC generator to a predetermined magnitude. The control circuit elements include a Zener diode connected to a voltage dividing resistance network connected between the other end of the field winding put at a positive potential and ground to provide a reference voltage source, and a control transistor responsive to the operation of the Zener diode to effect the ON-OFF control of the power transistor.
Conventional semiconductor regulators as described above have had circuit elements including transistors, diodes, resistors and capacitors separately disposed on a ceramic substrate to form the hybrid thick film integrated circuit thereon. This has resulted in a great number of bondings and therefore in a decrease in reliability. Also, since the respective circuit elements are separately bonded to the hybrid thick film integrated circuit, it has been difficult to automatically assemble the circuit elements into the hybrid thick film integrated circuit resulting in an extremely poor mass-productivity. In addition, due to a large number of the circuit elements used, the ceramic substrate has been large and, as a matter of course, required to be encased in a large casing resulting in the disadvantage that the semiconductor voltage regulator becomes large-sized.
Accordingly, it is an object of the present invention to eliminate the disadvantages of the prior art practice as described above by the provision of a new and improved construction of a semiconductor voltage regulator device high in reliability and easy to be automatically assembled while being small-sized.